Respiratory System and disease Flashcards
Label the structure of the lungs (airways)
Describe the passage of air from the trachea to the alveoli
- Trachea
- Primary Bronchi
- Secondary Bronchi
- Tertiary Bronchi
- Bronchioles
- Terminal Bronchioles
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
How does the structure of the airways change from the trachea down?
- Cartilage rings are replaced with cartilage plates and then from the therminal bronchioles and beyond there is no cartilage
- Epithelium changes from pseudo-stratified columnar to simple columnar to cuboidal
- The number of cilia decline
- The number of goblet cells decreases
- The amount of smooth muscle increases
Describe inspiration
- The respiratory centre in the brain sends a signal to initiate a breath
- The muscle of inspiration are initaated and start to contract
- The diaphragm contracts and descends
- The rib cage swings up and out increasing the volume within the thorax
- the intrapulmonary pressure starts to drop
- the pleural pressure in the pleural space becomes more negative because of rib cage movement
- intrapulmonary pressure becomes les than atmospheric pressure
- air is moved into the lungs until an equilibrium is reached
- air movement stops
Describe expiration
- The respiratory centre in the brain stops initataing inspiration
- The respiratory muscles relax
- The diaphragm moves up
- The rib cage moves down and in
- The lungs recoil due to their elastic properties (elastic recoil)
- Intrapulmonary pressure rises
- Intrapleural pressure becomes less negative
- Air leaves the lungs
- Air movement stops
What is lamina flow and how can we achive this in the larger airways?
Lamina flow is smooth straight air flow that fills the lungs more effectively. It can be achived by nasal breathing
What are the pleura?
two membranes with a space inbetween. There is the periatal pleura which coats the inside of the thorax and the viseral pleura which coats the outside of the lungs
Describe the interpleural space
- It is a fluid filled negative pressure space
- The fluid enables the pleura to rub together without damage
- The negative pressure stops the lungs from collapsing in on themselves
Describe the conducting zone
- It’s from the trachea to the terminal bronchioles
- No gas exchange takes place
- gas transport is by convection
- Held open by rings of cartilage, cartilagenous plates and smooth muscle
- This is the anatomical dead space
Describe the respiratory zone
- From the respiratory bonchioles to the aleveoli
- Gas exchange occurs at the alveolar-capillary membrane
- Gas transport by diffusion
- Held open only by pressure
- Large surface area in this zone for diffusion
Describe compliance
Change in volume ÷ change in pressure
Affected by:
- Residual volume
- Opening and cloding pressures of alveoli
Name factors that reduce compliance
- Small airway collapse (atelectasis)
- Fibrosis
- Pneumothorax
- obesity
- pulmonary vascular engorgement (lungs getting too backl pressured with blood)
- Pleural effusion
where is the most airway resistance?
- In the medium and larger airways (80% of resistance)
What factors determine airway resistance?
- High lung volume
- Low lung volume
- Very contracted brochial smooth muscle
- Airyway obstructions (secretions,pus,blood etc)
- Tissue resistance (e.g. in cystic fibrosis)
what are the three patterms of airflow through airways?
- Laminar flow - small airways
- Turbulent flow - large airways
- Transitional flow - medium airways especially at branch points
